Basically, he's painting over the image on the computer, and the incredible process takes days, but the end results are worth it. He produces such high-quality images that they can be printed on canvas up to 48" high x 108" wide. I recommend looking at the pieces up close here where you can zoom in to see the brush strokes. It's pretty cool! He also has a few other pieces available for purchase in addition to the two above including one of Darth Vader! Enjoy!
And May the 4th be with you!